How to Make a Birdhouse with a View: Building a Spy Window Nest Box
This little window birdhouse gives us a peek inside the nest box as the parent birds build their nest, incubate their eggs, and feed their young. The clear plastic back offers a unique view into the birds' world as they raise their next generation of young. Hang the birdhouse in a protected area for a front row seat. It's fun and interesting to watch as the babies grow and joust for space until they are big enough to leave the nest. And it's rewarding to have built the nest box that provided the safety and security where the brood was raised.
The spy window birdhouse is easy to make and it will attract a variety of cavity-nesting birds including bluebirds, chickadees, and wrens. Unlike the commercial window birdhouses that attach to the glass with suction cups (which might come unstuck and fall to the ground), this little birdhouse is designed to hang from a sturdy cable. The front features a repurposed metal drawer pull awning to shade and protect the entrance from the rain. A salvaged star adds a bit of whimsey to transform a basic box into a useful piece of yard art.
Built for the Birds
This birdhouse is designed to meet the needs of small cavity-nesting birds—the types of birds that will move into a birdhouse to raise their young. Birds are very selective when searching for a place to raise their families. Bluebirds, chickadees, wrens, finches, nuthatches, and titmice seek out abandoned woodpecker holes and tree cavities for nesting sites. When natural nesting sites are scarce, these birds will readily move into a birdhouse that's built to their requirements. The size of the entrance hole, the amount of floor space, good air circulation, the placement of the birdhouse in your yard, and protection from predators and from the weather are all important considerations. I've built hundreds of birdhouses over the years that successfully fledged many generations of baby birds.
The Cutting List
I used pine to build the birdhouse along with a small piece of plexiglass for the window. Pine boards are cheap and easy to find at the local home improvement store, and it takes stain well. Cedar and redwood are also good choices for building birdhouses, though a bit more expensive. Be selective and look for boards that are flat and relatively free from knots.
Cut the boards of your choice into the following dimensions:
- Front: 9" L x 5-1/2" W
- Back: 5" L x 5-1/2" W
- Sides: 5-3/4" L x 4-3/4" W
- Floor: 4-5/8" L x 4" W
- Roof A: 6-1/2" L x 5-1/2" W
- Roof B: 6-1/2" L x 4-3/4" W
- Plexiglass Window: 5-1/2" L x 5" W
Making an Entrance
The spy window birdhouse is designed for bluebirds, chickadees, wrens, and other small cavity-nesting birds. The overall height is not critical; however, the diameter of the entrance hole is very important for letting these smaller birds in, yet keeping out the larger competitors such as starlings and sparrows. An entrance hole drilled to 1-1/2" diameter works well for the eastern bluebird. The western and mountain bluebirds prefer the slightly larger 1-9/16" diameter entrance. Wrens will happily move into birdhouses with a smaller 1-1/4" opening.
Cut the front and back pieces to length, then measure and mark the center point of the top edge to cut the peaks. I use a miter saw to make 45-degree angle cuts.
I drilled the entrance hole with a 1-1/2" Forstner bit, centering the hole across the front section and up 5" from the bottom edge.
Framing the Window
There are several different ways to attach the plexiglas window to the back of the birdhouse. On my original window birdhouse, the birdhouse hung from two eye screws attached to the roof and the plastic panel slid into slots that I cut into the side pieces. While this worked fine, it was difficult to clean out the nest box between broods.
In this version, the birdhouse hangs from a cable that's threaded through small holes drilled through the peaks of the front and back sections. This is much stronger than threading the eye screws into the roof. The plexiglass window is attached with four small screws that are easily removed for cleaning out the inside of the box.
The back section fits into notches that are cut into each of the side pieces. Note that the front and back pieces are 1/4" longer than the side pieces. When the nest box is assembled with all of the bottom edges aligned, the sides are 1/4" shorter than the front and back (not including the peaks). This creates a gap under the roofline for air circulation and helps to cool the interior of the birdhouse.
For this build, the back edge is 2" high. The notch in the sides are 1-3/4" long, allowing for 1/4" to create a gap. When assembled, the back section will extend 1/4" above the side pieces to create an opening for airflow.
Notch Out the Side
The notch is 3/4" wide to match the thickness of the back section. I cut out the notches using a band saw, though a jig saw or hand saw would work just as well. Test the fit of the back piece into the side notches and when you are satisfied with the results, attach the back to the side pieces with weather resistant glue and nails.
Some Assembly Required
The sides, front, and back pieces are assembled using water-resistant glue and nails. Align the bottom edges of the sides with the bottom edge of the front section, then secure the pieces together with glue and nails.
To build the roof, attach the two roof sections together at a 90-degree angle with more nails or screws. Position the larger 5-1/2" wide piece (Roof A) so it overlaps the smaller 4-3/4" wide piece (Roof B), forming a peaked roof. Sand and stain the roof pieces (if desired) before attaching the roof to the nest box assembly.
The back edge of the roof is positioned flush with the edge of the back of the birdhouse. The front part of the roof forms an overhang to protect the entrance hole from the rain.
I like to fill the nail holes with putty. When sanded smooth and painted, this extra step gives the birdhouses a finished look.
Fitting the Floor
Now that the subassembly of the birdhouse has three sides, it's time to test fit the floor. If needed, trim the edge(s) for a nice fit.
The floor needs drainage holes to allow any rainwater to drain away. The openings in the floor also increase the air flow by drawing cooler air in through the floor, then up and out through the side openings under the roof line. Drilling a few 1/4" diameter holes through the floor will work, though I prefer to clip off the corners.
A power miter saw makes quick and easy to about 1/2" off each of the corners. After positioning the floor section on the saw to slice off the first corner, mark its location on the miter saw and make the cut. Then line up the other edges with the mark for each of the remaining cuts.
Add the Window
The plexiglass window is attached to the birdhouse with four pan-head screws. I pre-drilled the holes through the plexiglass, using a bit that is just slightly larger than the diameter of the screw threads. This lets the screws slip easily through the holes without binding and reduces the chances of cracking the plastic. The oversized heads of the screws hold the plexiglass firmly in place.
A quick spray of black paint protects the screws from rusting and looks good against the white painted birdhouse.
Ready for Paint
Sand all of the edges to round over the corners and smooth the joints. Breaking the sharp corners gives the birdhouse a finished look and allows the paint and stain to adhere better. After sanding, paint or stain the exterior of the birdhouse. I only paint the outside, leaving the interior natural for the safety of the baby birds.
I painted the exterior white and the roof red. The light-colored background is a good canvas for adding details and contrasts nicely with the dark red roof. The star is a salvaged metal ornament that's painted red. The awning over the entrance is a repurposed metal drawer pull handle that's painted black and attached with a couple of screws.
The final step is adding the cable for hanging the birdhouse. The green 1/16" diameter cable is plastic-coated, about 18" long, and available at the local home center for less than $.50 per foot. Thread one end of the cable through the hole drilled in the peak, knotting the end on the inside of the box; a simple overhand knot works fine.
Thread the other end of the cable through the hole in the other peak, then tie off the end. The new spy window birdhouse is ready for occupancy!
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Building a Window Birdhouse (attaches with suction cups)
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
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© 2019 Anthony Altorenna